Cardiac rhythm management (CRM) systems often employ an implantable medical device (IMD) coupled to an endocardial surface of a patient's right heart via one or more medical electrical leads. Typically the one or more leads include electrodes for both stimulating the heart and sensing electrical activity of the heart. Alternatively, or in addition to the electrodes, leads may include means for therapeutic and/or diagnostic fluid infusion. In order to provide better management of cardiac conditions, the one or more leads may also include a physiological sensor. In many cases, it is desirable that all the necessary elements, including electrodes and/or fluid infusion ports and a physiological sensor, be carried on a single lead body wherein locations of each element along the lead body accommodate proper function to meet the therapeutic objectives of the CRM system. In order to accommodate the proper positioning of all the desired elements along a lead body, a sensor assembly includes an adaptor to route conductors past the sensor to additional elements carried by the lead body.